In EPA lingo, the chemicals are in cleanup projects called "operable units." The San Gabriel Valley Superfund problem is actually four areas of groundwater contamination. Within those sites, area one has five cleanup projects (El Monte, Richwood, South El Monte, Suburban Water Systems, and Whittier Narrows). Area 2 is Baldwin Park. Area 3 is Alhambra. Area 4 is Puente Valley. So, eight operable units all together.

Cleanup at those units is the job of the EPA, the regional water board, and one specially created local organization. California's state legislature created the San Gabriel Basin Water Quality Authority to administer federal and California money for groundwater treatment programs. The authority's authority extends over the San Gabriel Valley, Three Valley, and Upper San Gabriel Valley Municipal Water Districts, as well as cities in the region whose water doesn't come through those districts.

Two kinds of wells matter in the SGV: water supply wells, that bring aquifer water to homes and businesses, were first. Testing at hundreds of these wells in the 80s and 90s found more than two-thirds of them were polluted. Andmore wells have opened. Some drinkable water wells got contaminated by pollution moving in underground aquifers.

For example, in El Monte, groundwater contamination started in the shallow aquifer, up to 100 feet deep. Now it's moved, and for water purveyors who didn't protect deeper wells or clean them up, these supplies have effectively dried up.

Monitoring wells are a more recent development. Each of the operating units have cleanup projects at slightly different places in the process. The EPA looks at some monitoring wells, as they're establishing the nature and extent of the hazard. Then, as cleanups come on line (in the form of treatment facilities, many of which pump water out of the ground, purify it, and drop it back), the locals do the monitoring in the long run.

EPA's Superfund folks tout the success of cleanup efforts at some sites. The San Gabriel Basin Water Quality Authority says it has taken 45 tons of pollutants from water pumped in the last 18 years or so. And they've cost homeowners in the region about $7.25 a year in assessments on average.

One reason all this is important? State politics. The now-delayed $11 billion water bond originally built in the legislature in 2009 would have provided a billion dollars for groundwater cleanup around the state, about 100 million of that for the San Gabriel Valley.

More chronically, aquifers were a safe, local, cheaper source of water for San Gabriel Valley, at least, before we started spilling rocket fuel and other chemicals in them. As the cost of importing water from the Delta and from the Colorado River rises, as climate change imperils the size of those supplies, water experts, and federal and local politicians have all said the stakes are rising for cleaning up the valley's backyard.

Previously in Pacific Swell

KPCC's Molly Peterson on a Gilligan's Island style tour of environmental stories in and affecting Southern California. Named for the Yvor Winters poem: "The slow Pacific swell stirs on the sand/Sleeping to sink away, withdrawing land..."
Follow the blog at @PacificSwell and Molly at @KPCCmolly.